[devops] Match Tahoe bots on 'Tahoe'.

[rolfbjarne]

That way we don't limit ourselves to bots with Version=26.0 (but we can also
run on bots with minor OS updates, such as Version=26.3).

[Copilot]

Pull request overview

Updates the Azure DevOps macOS Tahoe (26) test stage agent selection so the pipeline can run on Tahoe bots without being pinned to a specific Agent.OSVersion (e.g., allowing 26.3 as well as 26.0).

Changes:

• Replaces the Tahoe stage demand from a specific OS version match (Agent.OSVersion -equals 26.0) to a different agent-matching demand.

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[Copilot]

Using Agent.Name -equals Tahoe is likely too restrictive/incorrect for selecting all macOS Tahoe bots: Agent.Name is the individual ADO agent name (typically unique), and this repo consistently uses the custom capability macOS.Name to select the OS (see Monterey/Ventura/Sonoma/Sequoia entries just above). To match any Tahoe machine regardless of minor OS version, switch this demand to macOS.Name -equals Tahoe (or another dedicated capability meant for OS selection) instead of Agent.Name.

Suggested change

	"Agent.Name -equals Tahoe",
	"macOS.Name -equals Tahoe",

[rolfbjarne]

Dup of #24851.